Because of this thread I've been searching for similar problems with other DLPs, and it's apparently common enough to inspire comments on various forums.
It's impossible to assess percentages, but the whole issue makes me wonder about failure rate on DMDs.
Some years ago when I was assessing what kind of display to buy I was attracted to LCOS because of the absence of movable mirrors with that technology. DLPs made me a little nervous because I reasoned that extremely tiny moving parts, moving continuously, might experience some failure.
So is this an endemic problem with DLP?